Abstract: Blasting load is a major dynamic disturbance factor of rock slope excavation in water conservancy and hydropower projects. Displacement often changes abruptly in the process of blasting excavation. In association with measured displacement data of a jointed rock slope, we investigated into the mechanism and variation of the abrupt change of displacement of the jointed rock mass slope induced by blasting load via numerical simulation. We also probed into the influence of blasting parameters on the abrupt changes of displacement. Results indicate that the abrupt change of displacement of the jointed rock mass is caused by the sudden release of strain energy accumulated in the rock mass during the boosting load. The amount of displacement's abrupt change is determined by both the peak of accumulated strain energy and the release rate of strain energy. The larger the peak value of blasting load and the longer the boosting time, the more strain energy is accumulated. The shorter the depressurization time, the faster the strain energy release rate would be, resulting in a larger abrupt change of displacement.

Key words: jointed rock mass, slope, blasting load, displacement, strain energy